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UNITED STATES ATENT OFFIoE.

FREDERICK S. BARFF, OF KILBURN, ENGLAND.

IMPROVEMENT IN PROCESSES OF PROTECTING IRON SUR F ACES.

Specification forming part of Letters Patent No. 182,148, dated September 12, 1876; application filed August 14, 1876.

To all whom it may concern:

Be it known that I, FREDERICK SETTLE BARFF, of Kilburn, in the county of Middlesex, England, professor of chemistry, have invented Improvements in the Protection of Iron Surfaces, and in Cleaning the Same, of which the following is a specification:

This invention relates, first, in effecting, or in the production of, a protective coating or film of oxide or of oxides of iron upon the surfaces of objects composed either of iron or steel, by submitting such objects, when at an elevated temperature, to the action of steam, or by submitting the, same to the ac-' tion of superheated steam; second, in effecting the removal or deoxidation of the oxide or oxides of iron or rust existing upon the surface of the iron or steel objects to be treated, by submittingthe same, at an elevated temperature, to the action of hydrogen.

In carrying out the first part of my invention, I place the objects composed of iron or steel in a muffle or chamber, so constructed as that it may be in part or wholly closed, and so that the contents of the interior of such muffle or chamber may be raisedby means of external heat to an 'jzeleyated temperature; and when the objects or articles have acquired a temperature sufficiently'ele vated to cause the decomposition of steam or of aqueous vapor when brought into contact therewith, I inject the same, and I continue the action of the steam, or of the. aqueous vapor, until the desired protective film or coating lot oxide has been produced, or, in

stead of submitting the objects or articles composed either of iron or of steel to the action of heat in the manner hereinbefore men? tioned, I place the same in a chamber capable of being wholly or partially closed, and I 4 cause superheated steam to be admitted and to circulate therein, and I continue thisoper ation until the desired protective film or coating of oxide has been produced.::;

In carrying outthe second part of'my vention, I cause the objects orvarticles, com-V posed either of iron torsteel, from which it is desired to remove or. reduce any coating or film of oxide of ironor rust prior to their being submitted to the before-mentionedoxt dizing process to a deoxidizing process and' for this purpose I place such objects or arti-' cles or objects have attained the desired tem-- perature, or such a temperature as will cause the reduction of the oxide of iron to be effected by means of hydrogen, I admit hydrogen gas obtained or resulting from the .before-mentioned oxidizing process, or obtained fromother sources, and I cause the same to come in contact with the articles or objects until the desired reduction of the oxide has been effected.

After the objects or articles have been submitted to the first part of my invention, I prefer to remove them when at an elevated temperature, and to immerse them in oil, in the case of objects .or articles composed of iron or steel, whereby the protective coating :01 film will be rendered more tough and permanent, and in the case of objects or articles composed of steel the temper which they will have lost may be recovered, or any desired temper may beobtained, as is well understood in the arts. I claimy 1. The process of protecting iron surfaces from rust orcorrosionbysubmittin g the plates, articles, or objebts composed of the same, to an' elevated temperature, in conunction with superheated steam or aqueous vapor, so, that a coating-or film of oxide of iron, or ;wl 1 atis commonly kpown as black oxide of iron, maybe formed thereon.

2. Thejprocess of reducing the oxide or oxides of iron or rust whenfexistin'g upon the plates, articles,,o'r" objects prior to their. being treated in the manner hereinbfore described, bysubmitting' said -plates,' articles, or objects" to the actio nof hydrogen gas, asset forth.

:In witness wllere'of I havesig'ned my name to this specification in thepresence of two subscribing witnesses ,5 FREDERICK SETTLE BARFF.

Witnesses:--

' F DK- -DY 47.-1;m 0zhs lan l liel'cls, London. Oa S-M L w 47*Lz'ncolns Inn Fields, London.

or steel. 

